From a4258c4f7ed6293f6557b34d5b21138ef43ba901 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Mon, 15 Jan 2001 13:31:18 +0000
Subject: Use the name crt0.o, and cp it to $(TOPDIR)/libcrt0.o

---
 libc/sysdeps/linux/i386/Makefile |  12 +++-
 libc/sysdeps/linux/i386/crt0.S   | 123 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+), 2 deletions(-)
 create mode 100644 libc/sysdeps/linux/i386/crt0.S

(limited to 'libc/sysdeps/linux/i386')

diff --git a/libc/sysdeps/linux/i386/Makefile b/libc/sysdeps/linux/i386/Makefile
index 9c487bfd1..a6b185c21 100644
--- a/libc/sysdeps/linux/i386/Makefile
+++ b/libc/sysdeps/linux/i386/Makefile
@@ -25,7 +25,10 @@ include $(TOPDIR)Rules.mak
 LIBC=$(TOPDIR)libc.a
 ASFLAGS=$(CFLAGS)
 
-SSRC=_start.S longjmp.S setjmp.S #_start.S #clone.S
+CRT0=crt0.S
+CRT0_OBJ=$(patsubst %.S,%.o, $(CRT0))
+
+SSRC=longjmp.S setjmp.S #_start.S #clone.S
 ifeq ($(UNIFIED_SYSCALL),true)
 	SSRC += __uClibc_syscall.S
 endif
@@ -37,13 +40,18 @@ COBJS=$(patsubst %.c,%.o, $(CSRC))
 OBJS=$(SOBJS) $(COBJS)
 
 
-all: $(OBJS) $(LIBC)
+all: $(OBJS) $(CRT0_OBJ) $(LIBC)
 
 $(LIBC): ar-target
 
 ar-target: $(OBJS)
 	$(AR) $(ARFLAGS) $(LIBC) $(OBJS)
 
+$(CRT0_OBJ): %.o : %.S
+	$(CC) $(CFLAGS) -c $< -o $@
+	$(STRIPTOOL) -x -R .note -R .comment $*.o
+	cp $*.o $(TOPDIR)/libcrt0.o
+
 $(SOBJS): %.o : %.S
 	$(CC) $(CFLAGS) -c $< -o $@
 	$(STRIPTOOL) -x -R .note -R .comment $*.o
diff --git a/libc/sysdeps/linux/i386/crt0.S b/libc/sysdeps/linux/i386/crt0.S
new file mode 100644
index 000000000..08e406cc6
--- /dev/null
+++ b/libc/sysdeps/linux/i386/crt0.S
@@ -0,0 +1,123 @@
+/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+
+/*  If you don't know what is going on here, check out 
+    http://linuxassembly.org/startup.html
+    For a description of the stack layout.
+     -John Beppu, and Erik Andersen
+*/
+
+.global __environ
+.global __errno
+.global _start
+.global exit
+.global main
+.global __stdio_close_all
+.global _void_void_null_func
+.global _start_exit
+
+.text
+_start:
+	/* First locate the start of the environment variables */
+	popl %ecx	/* Store argc into %ecx */
+	movl %esp,%ebx  /* Store argv into ebx */
+	movl %esp,%eax  /* Store argv into eax as well*/
+	movl %ecx,%edx	/* Stick argc into %edx so we can do some math in a sec */
+	leal 4(%eax,%edx,4),%eax
+
+	/*  [ register layout ]
+
+	    sizeof(char*) == 4
+	    %ecx = argc	    ; 0(esp)
+	    %ebx = argv	    ; 4(esp)
+	    %eax = env	    ; argv + (argc * 4) + 4
+	*/
+
+
+	/* Set up an invalid (NULL return address, NULL frame pointer)
+	   callers stack frame so anybody unrolling the stack knows where
+	   to stop */
+	xorl %ebp,%ebp  /* NULL */
+	pushl %ebp      /* callers %cs */
+	pushl %ebp      /* callers %eip (return address) */
+	pushl %ebp      /* callers %ebp (frame pointer) */
+	movl %esp,%ebp  /* mark callers stack frame as invalid */
+
+	/* Now set the environment, argc, and argv where the app can get to them */
+	pushl %eax      /* Environment pointer */
+	pushl %ebx       /* Argument pointer */
+	pushl %ecx      /* And the argument count */
+
+	/* Make sure we are not using iBCS2 personality. (i.e. force linux).  */
+	movl $136,%eax
+	sub %ebx,%ebx
+	int $0x80
+
+	/* set up __environ */	
+	movl 8(%esp),%eax
+	movl %eax,__environ
+
+	/* Tell libc to initialize anything it needs to do */
+	call __libc_init
+	/* call __malloc_init */
+	call __init_stdio
+
+	/* Ok, now run main() */
+	call main
+	pushl %eax
+	call exit
+
+	/* Just in case _exit fails... We use int $0x80 for __exit().  */
+	popl %ebx
+	.align 4,0x90
+_start_exit:
+	movl $1,%eax
+	int $0x80
+	jmp _start_exit
+	.align 4,0x90
+_void_void_null_func:
+	ret
+
+.weak __libc_init
+__libc_init = _void_void_null_func
+
+/*
+.weak __malloc_init
+__malloc_init = _void_void_null_func
+*/
+
+.weak __init_stdio
+__init_stdio = _void_void_null_func
+
+.weak __stdio_close_all
+__stdio_close_all = _void_void_null_func
+	
+.data
+__environ:
+        .long 0
+.weak environ
+.align  4
+environ = __environ
+
+.data
+__errno:
+        .long 0
+.weak errno
+.align  4
+errno = __errno
-- 
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